Method for storing data in a data storage space of a server, associated storage administration device and server comprising such a device

ABSTRACT

A method of storing data in a memory of a server comprising the following steps:
         partitioning the memory into separate partitions;   receiving content and storing said content in one of said partitions;   a number, called the number of replications, is associated with each partition; distinct numbers of replications being associated with distinct partitions;   a number of replications n of said received content having been defined for said content, selecting a partition with which said defined number n of replications has been associated, storing said content comprising the storing of n replications of said content in said selected partition.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present Application for Patent is a National Stage Entry ofInternational Application No. PCT/EP2020/076846, filed Sep. 25, 2020,which claims priority to French Patent Application No. 19 10684, filedSep. 27, 2019. The disclosures of the priority applications areincorporated in their entirety by reference herein.

BACKGROUND OF THE TECHNOLOGY

The present invention relates to storage in a server's data storagespace.

Such a server is, for example, a media server of an in-vehicleentertainment system comprising entertainment user terminals for apassenger transport vehicle, said media server being carried on boardsaid mobile vehicle and connected to in-vehicle entertainment userterminals via an in-vehicle local area network.

Such mobile entertainment systems can be found in aircraft, mainly onlong-haul commercial aircraft, and are also known as In-FlightEntertainment (IFE) systems.

The entertainment terminals are usually connected via a wired orwireless network to the on-board media server which is also part of theIFE system.

Thus, in order to be accessible to the entertainment terminals, thecomputer content is first loaded onto the on-board media server.

Volumes of media content, for instance volumes of content offered onboard a vehicle, are growing, and with increasing resolutions (2K, 4K,8K, etc.) and quality video standards (HDR, HDR10, HDR10+, DolbyVision), the volume of storage required will continue to grow.

In addition, each item of media content is often stored several times inthe storage space to compensate for hardware failures.

There is therefore a need to manage the storage space of a server inwhich multiple copies of data sets must be stored.

BRIEF SUMMARY

To this end, according to a first aspect, the invention proposes amethod of storing data in a data storage space of a server, comprisingthe following steps implemented by an electronic storage spacemanagement module:

-   -   partitioning the storage space into a plurality of distinct        partitions;    -   receiving a set of data to be stored and storing said set of        data in one of said partitions;        said method being characterised in that it further comprises the        following steps: partitioning the storage space into a plurality        of distinct partitions;    -   receiving a set of data to be stored and storing said set of        data in one of said partitions;        said method being characterised in that it further comprises the        following steps:    -   a number, called the number of replications, is associated with        each partition; distinct partition numbers being associated with        distinct partitions;    -   a number of replications n of said received data set having been        defined for said data set, selecting a partition with which said        defined number n of replications has been associated, storing        said data set comprising the storing of n replications of said        data set in said selected partition.

The invention thus provides a solution to facilitate the storage of datasets, some of which are to be stored in multiple copies. The usefulstorage volume is thus optimised. The ratio between useful volume andgross storage volume is optimised, while maintaining the best possiblecompromise of resilience versus performance. The time required toimplement the storage of content or to update it, for example followinga change in the number of replications to be stored, is reduced.

In embodiments, the method of storing data in a data storage spaceaccording to the invention further comprises one or more of thefollowing features:

-   -   the storage space is distributed over a plurality of electronic        storage units and if the number n of replications of said        received set is greater than 2, the storage of said data set is        implemented by the electronic storage space management module        under the following condition: Distinct replications of said        data set are stored, in said selected partition, on distinct        units, said units being cards or disks of the same card;    -   the partitioning is updated, including changing the sizes of the        partitions assigned to numbers of replications, according to the        data sets to be stored;    -   said server is a media server for an on-board entertainment        system comprising entertainment user terminals for a passenger        transport vehicle, said media server being intended to be        carried on board said vehicle and to be connected to at least        one on-board entertainment user terminal via an on-board local        area network, the media server comprising:        -   said storage space, the data sets comprising media content;        -   a distribution module configured to distribute, via the            on-board local area network, to at least one user terminal            at least one item of media content stored in the storage            space;    -   the method comprises the following steps implemented by the        electronic storage space management module to free up space in a        partition associated with a number of replications:        -   a. calculating the current value of a preservation parameter            for each of a plurality of data sets for which the same            first number of replications has been defined, equal to said            number of replications associated with said partition; said            parameter representing a time divided by a number of            accesses to said content during said time;        -   b. selecting at least one data set to be deleted from said            partition based on a comparison of said current values with            each other;    -   step b further comprises a step of updating the number of        replications defined for said data set to be deleted, said        updated number being set as equal to a number of replications        associated with one of said partitions and strictly lower than        said first number;    -   steps a and b are implemented successively for each of the        partitions, starting with the partition associated with the        largest number of replications and continuing in descending        order of said numbers of replications associated with the        partitions.

In a second aspect, the present invention provides a device for managinga data storage space, said device being adapted to partition the storagespace into a plurality of distinct partitions, to receive a data set tobe stored, and to store said data set in one of said partitions;

said device being characterised in that it is adapted to associate anumber, called the number of replications, with each partition, distinctpartition numbers being associated with distinct partitions;

-   -   said device being adapted to, a number of replications n of said        received data set having been defined for said data set, select        a partition with which said defined number n of replications has        been associated, and to store n replications of said data set in        said selected partition.

In a third aspect, the present invention provides a server comprising adata storage space and a device for managing said data storage spaceaccording to the second aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These characteristics and advantages of the invention will becomeapparent upon reading the following description, given only as anonlimiting example, referring to the attached drawings, in which:

FIG. 1 is a schematic view of an aircraft equipped with an electronicentertainment system comprising entertainment terminals, not shown, anda media server in one embodiment of the invention;

FIG. 2 is a schematic of an electronic cabinet forming the media serverof FIG. 1;

FIG. 3 is a representation of the partitioning of the storage memoryspace in a disk of the server and in the whole storage space, in oneembodiment of the invention;

FIG. 4 is a flowchart of steps implemented in one embodiment of theinvention;

FIG. 5 is a flowchart of steps implemented in one embodiment of theinvention.

DETAILED DESCRIPTION

In FIG. 1, an aircraft 10 is shown in one embodiment of the invention:the aircraft 10 is equipped with an electronic entertainment system 16comprising entertainment user terminals, not shown, and a media server20.

The aircraft 10 is preferably an aircraft, in particular a commercialaircraft, such as a long-haul aircraft. The aircraft 10 is capable ofcarrying passengers, particularly a few dozen or even a few hundredpassengers. It should be noted that in other embodiments, the aircraftis replaced by a passenger transport vehicle of another type, such as atruck, bus, ship etc.

The entertainment system 16 on board the aircraft 10 is configured tobroadcast media content to the passengers of the aircraft 10, inparticular during the flight (e.g. movies, TV programmes, games, ormusic), and/or information on the course of the flight (altitude, speed,current position, distance traveled, etc.).

As an optional extra, the entertainment system 16 is configured tobroadcast practical information about, for example, the arrival airport,for example via announcements in audio and/or video form.

Each entertainment terminal is known per se, and is connected to themedia server 16 via a local area network, not shown, on board theaircraft 10.

Each entertainment terminal is, for example, attached to or integratedinto the passenger's own seat, or is attached to or integrated into theseat back in front of the passenger's seat. The seats are typicallyarranged in rows within the aircraft 10.

Each entertainment terminal, also known as a user terminal, comprises ahuman-machine interface (HMI), a processing module, an applicationmodule and a telecommunications module. The HMI includes, for example, atouch screen, or a screen and keyboard. The application module comprisesone or more application blocks. The telecommunication module comprises acontrol block and one or more telecommunication interfaces adapted totransmit and receive data. The processing module is adapted to controland coordinate the operation of the application module, the HMI and thetelecommunication module. In one embodiment, it comprises a processorand a memory, for example a hard drive or any other storage spacecapable of storing computer content received in particular via thetelecommunications module.

Each entertainment terminal is adapted to deliver to passengers thecomputerised media content offered by the in-flight entertainmentsystem. For example, following a passenger's selection of a fielddisplayed on the HMI screen of their entertainment terminal, theprocessing module is adapted to identify that a selection menu of one ofthe applications, for example a list of movies, should then bedisplayed. Then, upon detection of a film selection by the passenger,the processing module is adapted to trigger the display of the movie onthe screen. In addition to films, the content delivered by theapplications can be diverse: media content, e.g. movies, TV programmes,games or music, flight parameters (altitude, speed, etc.) and progress(e.g. using a “moving map”), and announcements (audio and/or video) bythe crew. The display is capable of displaying images corresponding tocomputer content distributed from the media server 20. More precisely,the computer content is received via the telecommunication module fromthe media server 20 in the form of a stream or stored in the memory ofthe terminal, after having been previously downloaded from the mediaserver 20 via the said telecommunication module.

Once a passenger has ordered the media content to be played via theentertainment terminal's HMI, the passenger can then access it, with themedia content being played (via audio and/or video) on the HMI of theiruser terminal. The user can thus have access to it for the entireduration of the content, or only a part of this duration if they stopearlier or if they only view some excerpts of it.

The media server 20 is connected to at least one entertainment terminal,preferably to each entertainment terminal, via an on-board local areanetwork.

When the on-board local area network is partially wired and partiallywireless, the media server 20 is for example wired to an entertainmentterminal in each row of seats, and said terminal wired to the mediaserver 20 is then connected via wireless links to the other terminals inthe row of seats.

Each wireless link is, for example, a radio link, such as a linkcomplying with at least one version of the IEEE 802.11 standard, alsoknown as the Wi-Fi™ standard, or a link complying with the Li-Fistandard, for example the IEEE 802.15.7 standard.

The media server 20 can be connected to an external electronic contentdelivery device 22 via a communication link 66, for example encrypted.In one embodiment, this connection is only implemented when the aircraft10, on which the server is carried, is on the ground, parked at theairport, as shown in FIG. 1 (the link 66 may be wired or wireless). Inanother embodiment, this connection is satellite-based and can takeplace even in flight.

The media server 20 comprises a data storage space 24, an electronicstorage control module 30, an electronic module 32 for interfacing withthe data storage space, an electronic partitioning module 34, and anelectronic distribution module 40.

In the example shown in FIG. 1, the media server 20 comprises aninformation processing unit 45 formed for example by a memory 46 and aprocessor 48 associated with the memory 46.

In the example of FIG. 1, the storage control module 30, the interfacemodule 32, the partitioning module 34, and the distribution module 40,are each in the form of software which can be executed by the processor48. The memory 46 of the media server 20 is then able to store storagecontrol software, interface software and distribution software. Theprocessor 48 in this case is able to execute each of the softwareprograms.

In a variant not shown, the storage control module 30, the interfacemodule 32, the partitioning module 34, and the distribution module 40are each in the form of a programmable logical component, such as a FPGA(Field Programmable Gate Array), or as a dedicated integrated circuit,such as an ASIC (Application-Specific Integrated Circuit).

When the media server 20 is in the form of one or more pieces ofsoftware, that is to say in the form of a computer program, it is alsocapable of being stored on a computer-readable medium, not shown. Thecomputer-readable medium is, for example, a medium that can storeelectronic instructions and be coupled with a bus from a computersystem. For example, the readable medium is an optical disk,magneto-optical disk, ROM memory, RAM memory, any type of non-volatilememory (for example EPROM, EEPROM, FLASH, NVRAM), magnetic card oroptical card. The readable medium in such a case stores a computerprogram comprising software instructions.

The data storage space 24 is adapted to store media content supplied toit by the external equipment 22 for subsequent supply to theentertainment terminals by the server 20.

In one embodiment, with reference to FIG. 2, the media server 20 isimplemented as an electronic cabinet comprising one or more power supplycards P, one or more network switch cards SW, and one or more electronicstorage cards B. Each of these cards is connected to a backplane (notshown).

A power supply card P is configured to convert electrical power receivedfrom an on-board power supply network into other electrical powersupplied to the electronic cards SW and B.

A network switch card SW is a card dedicated to communications with theon-board local area network on the one hand, and with the externalelectronic equipment 22 via the link 66 on the other. The network switchcard SW is also able to perform data routing between the aforementionednetworks on the one hand and the data storage cards B on the other hand,i.e. to implement a network switching functionality, such as Ethernetswitching.

A data storage card B is a card configured to store data, includingcomputerised media content for distribution to entertainment terminals.The data storage card B typically comprises at least one mass storagememory. In one embodiment, at least some of these data storage cards Bfurther comprise one or more CPUs, such as one or more processors, andare further configured for computing, for example to perform processingthat requires quite large calculation resources and that is performed inparticular on data stored in the storage space 24.

Beyond this hardware layer comprising the mass storage memory and theCPU, the data storage card B comprises software layers allowing theserver 20 to implement file management and orchestration of functionsimplemented by the server 20.

Each data storage card B comprises a number N_(d/b) separate hardwarestorage units, e.g. storage drives, e.g. SSDs. In this example, N_(d/b)is at least 2 and at most 4. For example, each SSD drive has a datastorage capacity of 8 TB (Terabyte) each. Each data storage card B thusoffers between 16 and 32 TB of storage capacity.

In the embodiment under consideration, the server 20 comprises a numberNb of data storage cards B, with for example Nb equal to at least 3 andat most 6. In this case, all the storage capacities offer an availablevolume between 16×3 and 32×6, i.e. between 48 and 196 TB.

All the storage capacities of the data storage cards B are aggregatedwithin the server 20, thanks in particular to the functions of thenetwork switch cards SW, in a logical way into one and the same filesystem called a “distributed file system”, constituting the data storagespace 24.

According to the invention, N is equal to the number of distinctreplication rate values considered, N being chosen to be greater than orequal to 2; an item of media content can thus be copied n times in thestorage space 24 with n

{n₁, n₂, . . . , n_(N)}, where_(i), i=1 to N is an integer.

For example, in a particular case under consideration, it is consideredthat an item of media content stored in the storage space 24 can bestored in one copy (replication rate TR equal to 1), in two copies(replication rate TR equal to 2) or in three copies (replication rate TRequal to 3): N is then equal to 3.

The replication rate defined for an item of media content can bedetermined in several ways, as will be described later.

Note that in another embodiment, non-consecutive replication rates willalso give a value of N equal to 3 with (TR equal to e.g. 1, 2 and 4).

The partitioning module 34 is configured to perform a partitioningoperation on the storage space 24 into N partitions ESP1, ESP2, . . .ESPN, and to associate with each partition ESPi the replication rate TRequal to n_(i), i=1 to N.

In one embodiment, all N rates are distinct and only one replicationrate is associated with any partition.

According to the invention, the media contents to be stored in thestorage space 24 with a replication rate TR equal to n_(i), i.e. inn_(i) copies, will thus be copied n_(i) times in the ESPi partition, asdescribed below.

In a known way, partitioning a storage space is the operation ofdividing it into partitions, or regions, in which the operating systemof the server 20 can manage their information separately and privately.There are different tools (fdisk, diskpart, disk.app etc.) to performand manipulate partitioning for different architectures, including MBR,GPT etc.

In one embodiment, the maximum replication rate RL is set equal to thenumber of disks physically present, i.e. Nb×N_(d/b). Such a highreplication rate is obviously at the expense of useful storage space.

The maximum replication rate for resilience to card loss is Nb.

The replication rate to maximise useful storage space is 1.

The local area network on board the aircraft 10 is a wired-only network,or a partially wired and partially wireless network, or a wireless-onlynetwork.

The storage control module 30 is configured to control the storage ofthe media content in the data storage space 24, in particular todetermine, in the data storage space 24, which media content to deleteand/or which content to be retained and/or the number of replications TRto be stored for each item of content to be retained or saved in thestorage space 24.

The storage control module 30 is further configured to provide to theinterface module 32, for each item of media content, a delete command ifthe content is to be deleted, or, if the media content is to beretained, to provide the value of the replication rate TR associatedwith it from among n₁, n₂, . . . , n_(N).

The interface module 32 is adapted to interface with the storage space24 to implement commands received from the storage control module 30,i.e. to delete media content or to store one or more copies of new oralready-stored media content in the storage space, depending on thereplication rates determined for the respective content.

The interface module 32 is, according to the invention, adapted tochoose the location in the storage space according to the replicationrate n_(i) defined for each item of media content: the interface module32 is thus adapted to select whichever one of the partitions in thestorage space 24 is associated with a replication rate equal to n_(i),i.e. the partition ESPi, and to store said content in n_(i) copies inthat selected partition ESPi.

Furthermore, in one embodiment, the interface module 32 is adapted tomeet the following constraints:

-   -   only one item of media content must be stored in a single SSD,        for content with a replication rate of 1;    -   as soon as the replication rate n_(i) is greater than or equal        to 2, copies of the same content must be stored in separate        cards.

The distribution module 40 is configured to distribute the correspondingmedia content to each entertainment terminal. For example, thedistribution module 40 is configured to stream the corresponding mediacontent to each entertainment terminal (in case of multiple replicationsof the content present in the storage space 24, the interface module 32is configured to select whichever one of the replications is used). Inthis case, the user of the entertainment terminal can access the contentas it is streamed.

Operations implemented by the media server 20 will now be explained, inparticular with the aid of FIG. 4 showing a flowchart 200 of a methodfor storing data in the server's data storage space, in one embodimentof the invention, the method being implemented by the media server 20.

In a step 201, a number N equal to the number of distinct replicationrate values considered having been set, the partitioning module 34partitions the storage space 24 into N partitions ESP1, ESP2, . . .ESPN, and associates with each partition ESPi the replication rate TRequal to n_(i), =1 to N, and where n₁<n₂ . . . <n_(N).

With reference to FIG. 3, we consider the particular case where thereare 3 distinct replication rates (N=3), these replication rates beingn₁=1, n₂=2, n₃=3. Each SSD 31 on each card B is partitioned into threevolumes, a first volume of size s1, which is part of the ESP1 spaceassociated with replication rate n₁, a second volume of size s2, whichis part of the ESP2 space associated with replication rate n₂, and athird volume of size s3, which is part of the ESP3 space associated withreplication rate n₃.

The useful volume available for each space ESPi, i=1 to 3, is thereforeequal to si×Nb×N_(d/b)/n_(i).

Thus, counting 8 TB per disk, of which 500 GB is reserved for theworking memory for the application of the entertainment system, withs1=2.5 TB, s2=4 TB, s3=1 TB at least in our case (i.e. for a number ofcards Nb equal to 3 and a number of disks per card N_(d/b) equal to 2),we obtain a useful volume of 15 TB for ESP1, a useful volume of 12 TBfor ESP2, 2 TB for ESP3, i.e. a total of 29 TB of useful volume in thestorage space 24.

Counting 8 TB per disk, of which 500 GB is reserved for the workingmemory, again with s1=2.5 TB, s2=4 TB, s3=1 TB at most in our case (i.e.for a number of cards Nb equal to 6 and a number of disks per cardN_(d/b) equal to 4), we obtain a useful volume of 60 TB for ESP1, auseful volume of 48 TB for ESP2, 8 TB for ESP3, i.e. a total of 116 TBof useful volume in the storage space 24.

The invention therefore provides a larger useful storage volume than inthe IFE servers of the prior art, in which a single replication rate isapplied, equal to 2, so that a gross volume available between 48 and 196TB gives a useful volume between 24 and 96 TB. This operation bypartitioning allows the segregation of replication management processes,as well as those of updating and unified access to the media catalogue.

In the case of a lost SSD drive, the loss of useful content is at most2.5 TB; in the case of a lost card B, the loss of useful content isbetween 5 (if there are 2 disks per card) and 10 TB (if there are 4disks per card).

The combinatorial range of possible choices in terms of the number ofpartitions N, the value of the replication rate associated with eachpartition, and the size of the partition is almost infinite. The size ofeach partition allows a trade-off between loss resilience and maximumusable volume.

In a step 202 of updating the storage space 24, following the receipt bythe server 20 of new content provided by the external electronicequipment 22 and/or in the context of updating the content already keptin the storage space, the storage control module 30 determines,according to predetermined control rules, which media content is to bedeleted from the data storage space 24, optionally updates thereplication rates of the content already stored, and determines thereplication rates of the newly received content to be saved in thestorage space 24.

Different rules for determining deletions and replication rates may beused by the storage control module 30; for example, a defaultreplication rate is chosen for any new content received, withreplication rates being updated over time, for example decreasing as thetime stored in the storage space increases, or for example in the mannerdescribed later with reference to FIG. 5.

The storage control module 30 then provides to the interface module 32,for each item of media content, a command to delete all of the content,or, if the media content is to be kept in the storage space 24, acommand to keep the content with the current value of the replicationrate TR associated with it among n₁, n₂, . . . , n_(N).

In a step 203, the interface module 32 receives these commands,interfaces with the storage space 24 to implement them, deletes anycopies of content determined as to-be-deleted; for any new contentreceived with a replication rate TR equal to n_(i), the interface module32 stores n_(i) copies of the new content in the partition ESPi; for anycontent that was already saved in the storage space 24 and whosereplication rate has been changed to n_(j), the interface module 32stores n_(j) copies of the content in the partition ESPj and deletes thecopy or copies of said content stored in the partition, distinct fromthe partition ESPj, in which said copy or copies were stored.

In one embodiment, the interface module 32 further complies with thefollowing constraints:

-   -   only one item of media content must be stored in a single SSD,        for content with a replication rate of 1; and/or    -   as soon as the replication rate is greater than or equal to 2,        copies of the same content must be stored in separate cards B.

Step 202 is implemented each time new media content is received by theserver to be stored in the storage space and/or each time the overallcontent of the storage space 24 is updated. In one embodiment, step 201is itself repeated, prior to step 202, when new replication rates forthe stored content are determined or when it is decided to change thenumber N of such rates.

Distribution to the entertainment terminals by the distribution module40 can then continue on the basis of this updated storage space 24.

Optionally, the invention further provides a solution for determiningthe content to be deleted from the storage space 24 and/or fordetermining the replication rates.

In such an embodiment, he storage control module 30 is configured tocollect, for each item of media content considered in the storage space24, the current value, known as AS, of the “audience score” indicator,which is representative of the number of views of the media content (tocover also the case of purely audio content for which the term views isinaccurate, we will speak hereafter of accesses).

The storage control module 30 is configured to collect, for each item ofmedia content considered in the storage space 24, the current value,known as AS, of the “audience score” indicator, which is representativeof the number of views of the media content (to cover also the case ofpurely audio content for which the term “views” is inaccurate, we willspeak hereafter of accesses, “accesses” in which the content is viewedand/or listened to).

Optionally, the AS value is further weighted by the number of “like” and“dislike” ratings left by passengers (example: AS×number of“likes”/number of “dislikes)”, or by a view duration ratio (e.g. theaverage time spent by passengers viewing the content divided by thetotal duration of the content).

AS can also be weighted by flight type (day/night), flight context(flight duration among short/medium/long haul), flight geography(departure airport, arrival airport), by seat class(business/economy/etc.).

In one embodiment, AS is weighted according to the aircraft's plannedfuture routes (for the same criteria as described here for theaircraft's past routes).

In embodiments, the storage control module 30 is configured todetermine, for each media content stored in the storage space 24,additionally the current value of the “decay rate” indicator,hereinafter referred to as DR indicator, proportional to the number offlight hours of the aircraft divided by the number of views of thecontent, i.e. DR=K. flight_hours/AS, with K being a constant that setsthe value based on a nominal number of views over a certain time range.

The storage control module 30 is configured to determine, based on thecalculated DR value, what will be the fate of the media content withinthe storage space 24, i.e. whether the content is to be deleted orretained and in the latter case, how many replications of the contentare stored.

In one embodiment, the storage control module 30 is in particularadapted to implement the operations to be performed by it which aredescribed below with reference to FIG. 5.

It will be further noted that when new media content is initiallyprovided by the external equipment 22 via the communication link 66, itis assigned for example an initial default number of replications, andthe interface module 32 is adapted to then interface with the storagespace 24 to implement storage of the new media content with that initialdefault number of replications.

The operation of the media server 20 in such an embodiment will now beexplained, in particular with the aid of FIG. 5 showing a flowchart 100of the storage control method according to the invention, the methodbeing implemented by the media server 20.

A current state of the storage space 24 is considered, storing items ofmedia content, each one associated with a respective replication rate,for example here equal to n₁, n₂ or n₃, where n₁<n₂<n₃, in this casen₁=1, n₂=2 and n₃=3 (of course, there may be any number N greater than 2of distinct replication values considered).

These items of content were initially provided by the externalelectronic equipment 22, then stored in the storage space 24 and aredistributed by the distribution module 40 to the user terminals, wherethe passengers can then consult that content. The logs of the perusal ofthe content by the passengers, indicating in particular the contentperused, the date and duration of perusal, and optionally an index ofthe passenger's satisfaction following their perusal of the content, arecollected by the terminals and then routed (possibly after agglomerationand processing to determine the indicators) via the local area networkto the storage control module 30 which collects them.

The set of steps 100 is for example implemented regularly for eachpartition ESPi, for example, every period T or else at each provision ofnew content during step 202, considering successively each partitionESPi, in decreasing order of associated replication rates, i.e. in thepresent case, first ESP3, then ESP2, then ESP1.

In one embodiment, the new media content to be stored in the storagespace 24 are associated with a predefined initial number of replicationsfrom among n₁, n₂ or n₃, which will not be changed before apredetermined time (e.g. until the next period T) by the processdescribed below implemented by the storage control module 30.

Considering the partition ESPi, in an initial step 101, the storagecontrol module 30 first places the media content stored in ESPiidentified as to-be-deleted, if any, in a list Li of content to bedeleted.

Then, the storage control module 30 determines whether the ESPipartition, after the contents identified in the list Li has beendeleted, has available space to accommodate the new content to be storedwith the predefined replication value n_(i).

If it does, the storage control module 30 transmits to the interfacemodule 32 the deletion commands corresponding to the list Li and thestorage commands for this new content with the predefined replicationvalue n_(i), and then repeats the set of steps 100 considering this timethe partition ESPi−1 (if i≠1).

If not, in a step 102, the storage control module 30 collects for eachitem of stored media content associated with the replication value n_(i)and not identified as to be deleted, the current AS value and thencalculates the current value of the indicator DR as a function of thatAS value, and then sequentially orders this content by its current DRvalue.

Then, considering each of these items of content one after another,starting from the one with the highest DR, the storage control module 30updates the number of replications associated with it by replacing thenumber n_(i) of replications associated with said content with thenext-highest number of replications, i.e. n_(i-1), if i≠1. When i=1, theupdate consists of adding the content in question to the list L1 ofcontent then stored in the ESP1 partition that is to be deleted.

After each update, the storage control module 30 determines whether theavailable space thus freed up in the partition ESPi allows the newcontent to be stored with the replication value n_(i), and if notrepeats the process, looking at the content with the next-highest DR,until the space freed up allows these new items of content to be storedin the partition ESPi.

Then, the storage control module 30 transmits to the interface module 32the deletion commands corresponding to the list Li, the commands tostore the new content with the predefined replication value n_(i) andthe commands to store in ESPi−1 the content already stored in thestorage space 24 but whose replication rate has been updated to n_(i-1).

Next, the same steps are implemented this time for the ESPi−1 partition,if i≠1.

The set of steps 100 therefore implements comparative logic processingfrom which the new items of content to be stored are excluded.

Step 203 is then implemented with the updates thus determined, i.e. theset of media content to be deleted from the partitions ESPi, i=1 to N,as indicated respectively in the lists Li, the new content associatedwith a replication rate ni to be stored in the partition ESPi and thecontent already stored in the storage space 24 but whose replicationrate has been updated during the implementation of the N iterations ofthe set of steps 100, successively applied to ESPN, . . . ESP1.

The more passengers have had access to a content, the higher thereplication rate of the resulting content; for each given period of timewithout the content being seen, the replication rate of the resultingcontent is greatly reduced; the available storage space and the numberof replications so far stored are also taken into account.

In a so-called autonomous embodiment, the current indicator(s) valuescollected are specific to the aircraft 16 and to the use of the mediaserver 20 within that aircraft.

In the described embodiment, free space was released in a partition ifthe space was determined to be insufficient; in other embodiments, aprocess of releasing free space within a partition is initiated bycomparing DR indicators of the content with each other even beforeinsufficient free space is detected.

In another semi-autonomous embodiment, the AS indicator slaves theaudience score specific to the aircraft 16 to a score consolidated by anexternal authority and supplied to the storage control module 30 (thisscore could be consolidated by a company at the level of its fleet ofaircraft, for example, or refined on a route regardless of the aircraftflying the route). This semi-autonomous embodiment also makes itpossible, in one embodiment, to automatically force the value of the DRindicator in order to automatically delete a given item of content (endof licence, editorial choice, etc.), to cancel it for contractualreasons or, on the contrary, to give it priority. The content stored onthe server is therefore updated regularly and automatically;

the deletion or continued storage of each item of content in question isdetermined automatically in some embodiments, as well as the number ofreplications stored; the use of the bandwidth required for theseoperations is minimised and controlled, as are the updates to the storedcontent.

The invention has been described above with reference to a server in anon-board entertainment system; it is of course applicable to a server inany other system, on-board or not, and in any field other than that ofpassenger entertainment.

1. A method of storing data in a data storage space of a server,comprising the following steps implemented by an electronic storagespace management module: partitioning the storage space into a pluralityof distinct partitions; receiving a set of data to be stored and storingsaid set of data in one of said partitions; wherein the method furthercomprises the following steps: a number, called the number ofreplications, is associated with each partition; distinct numbers ofreplications being associated with distinct partitions; a number ofreplications n of said received data set having been defined for saiddata set, n having any value from among said numbers of replicationsassociated with the partitions, selecting a partition with which saiddefined number n of replications has been associated, storing said dataset comprising the storing of n replications of said data set in saidselected partition.
 2. The method of storing data according to claim 1,wherein the storage space is distributed over a plurality of electronicstorage units and wherein if the number n of replications of saidreceived set is greater than 2, the storage of said data set isimplemented by the electronic storage space management module under thefollowing condition: distinct replications of said data set are stored,in said selected partition, on distinct units, said units being cards ordisks of the same card.
 3. The method of storing data according to claim1, wherein the partitioning is updated, comprising changing the sizes ofthe partitions assigned to numbers of replications, according to thedata sets to be stored.
 4. The method of storing data according to claim1, wherein said server is a media server for an on-board entertainmentsystem comprising entertainment user terminals for a passenger transportvehicle, said media server being configured to be carried on board saidvehicle and to be connected to at least one on-board entertainment userterminal via an on-board local area network, the media servercomprising: said storage space, the data sets comprising media content;a distribution module configured to distribute, via the on-board localarea network, to at least one user terminal at least one item of mediacontent stored in the storage space.
 5. The method of storing dataaccording to claim 1, comprising the following steps implemented by theelectronic storage space management module to free up space in apartition associated with a number of replications: a/ calculating thecurrent value of a preservation parameter for each of a plurality ofdata sets for which a same first number of replications has beendefined, equal to said number of replications associated with saidpartition; said parameter representing a time divided by a number ofaccesses to said content during said time; b/ selecting at least onedata set to be deleted from said partition based on a comparison of saidcurrent values with each other.
 6. The method of storing data accordingto claim 1, wherein step b further comprises a step of updating thenumber of replications defined for said data set to be deleted, saidupdated number being set as equal to a number of replications associatedwith one of said partitions and strictly lower than said first number.7. The method of storing data according to claim 5, wherein steps a andb are implemented successively for each of the partitions, starting withthe partition associated with the largest number of replications andcontinuing in descending order of said numbers of replicationsassociated with the partitions.
 8. A device for managing a data storagespace of a server, said device being adapted to partition the storagespace into a plurality of distinct partitions, to receive a data set tobe stored and to store said data set in one of said partitions; whereinthe device is adapted to associate a number, called the number ofreplications, with each partition, distinct numbers of replicationsbeing associated with distinct partitions; said device being adapted to,a number of replications n of said received data set having been definedfor said data set, n having any value from among said numbers ofreplications associated with the partitions, select a partition withwhich said defined number n of replications has been associated, and tostore n replications of said data set in said selected partition.
 9. Aserver comprising a data storage space and a device for managing saiddata storage space according to claim
 8. 10. A server according to claim9, said server being a media server for an on-board entertainment systemcomprising entertainment user terminals for a passenger transportvehicle, said media server being configured to be carried on board saidvehicle and to be connected to at least one on-board entertainment userterminal via an on-board local area network, the media servercomprising: said storage space, the data sets comprising media content;a distribution module configured to distribute, via the on-board localarea network, to at least one user terminal at least one item of mediacontent stored in the storage space.